func GetOauth2Client(clientId, clientSecret, cachePath string, promptUser bool) (*http.Client, error) {
cacheFile := oauth.CacheFile(cachePath)
config := &oauth.Config{
ClientId: clientId,
ClientSecret: clientSecret,
Scope: "https://www.googleapis.com/auth/drive",
RedirectURL: "urn:ietf:wg:oauth:2.0:oob",
AuthURL: "https://accounts.google.com/o/oauth2/auth",
TokenURL: "https://accounts.google.com/o/oauth2/token",
TokenCache: cacheFile,
}
transport := &oauth.Transport{
Config: config,
Transport: http.DefaultTransport,
}
// Return client if we have a valid token
if hasValidToken(cacheFile, transport) {
return transport.Client(), nil
}
if !promptUser {
return nil, errors.New("no valid token found")
}
// Get auth code from user and request a new token
code := promptUserForAuthCode(config)
_, err := transport.Exchange(code)
if err != nil {
return nil, err
}
return transport.Client(), nil
}
func main() {
flag.Parse()
// Set up a configuration.
config := &oauth.Config{
ClientId: *clientId,
ClientSecret: *clientSecret,
RedirectURL: *redirectURL,
Scope: *scope,
AuthURL: *authURL,
TokenURL: *tokenURL,
TokenCache: oauth.CacheFile(*cachefile),
}
// Set up a Transport using the config.
transport := &oauth.Transport{Config: config}
// Try to pull the token from the cache; if this fails, we need to get one.
token, err := config.TokenCache.Token()
if err != nil {
if *clientId == "" || *clientSecret == "" {
flag.Usage()
fmt.Fprint(os.Stderr, usageMsg)
os.Exit(2)
}
if *code == "" {
// Get an authorization code from the data provider.
// ("Please ask the user if I can access this resource.")
url := config.AuthCodeURL("")
fmt.Print("Visit this URL to get a code, then run again with -code=YOUR_CODE\n\n")
fmt.Println(url)
return
}
// Exchange the authorization code for an access token.
// ("Here's the code you gave the user, now give me a token!")
token, err = transport.Exchange(*code)
if err != nil {
log.Fatal("Exchange:", err)
}
// (The Exchange method will automatically cache the token.)
fmt.Printf("Token is cached in %v\n", config.TokenCache)
}
// Make the actual request using the cached token to authenticate.
// ("Here's the token, let me in!")
transport.Token = token
// Make the request.
r, err := transport.Client().Get(*requestURL)
if err != nil {
log.Fatal("Get:", err)
}
defer r.Body.Close()
// Write the response to standard output.
io.Copy(os.Stdout, r.Body)
// Send final carriage return, just to be neat.
fmt.Println()
}